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Years of industrial and agricultural growth
have left an indelible imprint on many formerly vibrant
US ecosystems.
While nature is adept at resilience, the depletion and
contamination of natural resources, especially water,
may affect human health and well-being, a new report suggests.
Released by the The Heinz Center - 'The State of the
Nation's Ecosystems' - offers a comprehensive look
at US countrywide ecosystem health. |
Following a similar report which the federally-funded environmental
think tank published in 2002, the new analysis was expanded
to include additional indicators - such as invasive species,
carbon storage and stream flows. Yet, the report's authors
do not hide the fact that data gaps prevent an even more detailed
assessment. "We don't have the entire environmental picture"
- said Thomas Lovejoy, president of the Heinz Center. Authors
called for federal and state action that would strengthen
and integrate environmental monitoring.
Among the findings, US freshwater resources are being continually
depleted and polluted. Between 1960 and 2000, freshwater withdrawn
for consumption increased 46 percent. Meanwhile, drought and
melting glaciers have reduced the flow of many water sources.
Contaminants - such as pesticides, fertilizers and medications
- have been detected in 'virtually all' freshwater
streambeds, the report said. Streams are contaminated above
benchmarks set to protect aquatic life in 57 percent of farmland
and 83 percent of urban and suburban areas. These pollutants
have contributed to growing 'dead zones' where aquatic
life cannot survive.
Contaminants at concentrations above the benchmark for human
health are found in 7 percent of urban and suburban streams.
Nitrate, a runoff of agricultural fertilizers, exceeds federal
drinking water standards in 20 percent of farmland groundwater
wells.
On a more positive note, many ecosystems - especially forests
- have remained intact due to conservation and sustainable
management. Timber growth has exceeded harvest - half of US
timberland is younger than 60 years old - which has allowed
forests to store more of the greenhouse gas carbon dioxide
in recent years than a decade ago.
However, wildlife within those ecosystems faces widespread
threats. One-third of native plant and animal species, excluding
marine species, are at risk of extinction. Global warming
is shifting the climate outside the threshold that many native
species can tolerate, which provides an advantage to invasive
species that have more general survival requirements.
Invasive species are also out-competing native species for
resources. More than half of US freshwater watersheds contain
at least 10 non-native fish species and only two watersheds
have no reported invasives, the report says.
Data gaps mentioned throughout the report include area measurements
of several ecosystems - such as wetlands, seagrasses, and
lakes - and of the rate that various ecosystems are being
converted into other uses. The report also says that biodiversity
and pollution data are inadequate for marine ecosystems.
"The field of environmental research is fraught by extremes
of political advocacy and inadequacy of scientific data" -
said William Clark, the chair of the project design committee
and an ecology professor at Harvard University.
To address the lack in data, which will be an ongoing challenge
as climate change continues to alter habitats worldwide, the
White House announced a plan to develop a new set of national
environmental indicators. After several attempts to impede
climate change reports throughout the current Bush administration
(Click
Here),
executive offices plan to consolidate water quantity and quality
indicators, which would measure the effect of climate change.
A report published by the US Environmental Protection Agency
last week expressed similar support for environmental indicators.
In this case, the agency said climate change thresholds should
be established for individual ecosystems to improve climate
adaptation plans. 'Understanding where thresholds have
been exceeded in the past - and where (and how likely) they
may be exceeded in the future - allows managers to plan accordingly
and avoid tipping points, where possible' - the report
said.
The Heinz Center recommended that Congress establish a national
system of exhaustive environmental and natural resources indicators.
"Once we have a decent system of monitoring what the current
system is, we can become much better at predicting what the
future is" - said Robin O'Malley, director of the center's
environmental reporting program.
To download The State of the Nation’s Ecosystems 2008
- Click
Here
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